{
    "$id": "newVariant",
    "type": "object",
    "properties": {
        "product": {
            "type": "string",
            "format": "objectid"
        },
        "title": {
            "type": "string",
            "isNotEmpty": true,
            "minLength": 2
        },
        "price": {
            "type": "string",
            "format": "amount"
        },
        "stock": {
            "type": ["number", "null"]
        }
    },
    "errorMessage": {
        "isNotEmpty": "This is my custom error message",
        "properties": {
            "price": "Should be a full 2 decimal value. Eg: 10.99"
        }
    },
    "required": [
        "product",
        "title",
        "price",
        "stock"
    ]
}